Apparatus for and method of joining stranded cable

ABSTRACT

Stranded cables are joined utilizing apparatus and method of this invention by coating individual strands of the end portions of the cables to be joined with a suitable cleaning liquid and then ejecting a fluid under pressure against such end portions to remove the liquid and any foreign particles from the end portions including forcing such particles along the length of the cable. The cleaned end portions are then fixed in an associated welding apparatus and welded together with a conventional welding device using an access port provided in the apparatus and the welding action provided assures that each cable strand is fused to the weld material. Any excess weld material is then removed from the welded end portions after removal from the welding apparatus and a tubular sleeve may be fixed in position over the welded junction to reinforce the high-strength weld.

United States Patent 4 4 mum? 4350 0 1 /1 W 9 9 1211. ll 2 2 2 1/1965Steele.......................::..

Primary Examiner-R. F. Staubly mm numlu n f eflkew SI r mwhw e JMSAM68724 34566 99999 lllll 246 6 1 2 367 2 85 55466 AssistantExaminer-George A. Montanye Attorney-Glenn, Palmer, Lyne, Gibbs &Thompson ABSTRACT: Stranded cables are and method of this invention bthe end portions of the cable cleaning liquid and then ejecting a fluidunder such end portions to remove the l cles from the end portionsincludin along the length of the cable The g apparatus and welded erwith a conventional welding device using an access port provided in theapparatus and the welding action provided assures that each cable strandis fused to the weld g apparatus the welded 1 228/44 then fixed in anassociated weldin togeth 219/517 material. Any excess weld material isthen removed from the 219/105 welded end portions after removal from theweldin 219/137 and a tubular'sleeve may be fixed in position overjunction to reinforce the high-strength weld.

References Cited UNITED STATES PATENTS 6/1900 McTighe..........H....5/1920 Pierce PATENIEB mu 1 I972 SHEET 1 [IF 3 THEIR ATTORNEYS PATENTEDm1 1 1m ales-4549 SHEET 2 OF 3 FIG-6 47 43 48 mvswrons DONALD D. RAGERROBERT L. HEFLIN DANA v. WILCOX BY jf THEIR ATTORNEYS PATENTEU JAN! 11912 3534.649

SHEET 3 BF 3 FIG-II 6O II II lLJl INVENTORS DONALD D. RAGER ROBERT L.HEFLIN DANA V. WILCOX THEIR ATTORNEYS APPARATUS FOR AND METHOD OFJOINING STRANDED CABLE BACKGROUND OF THE INVENTION It is very difficultto weld associated end portions of stranded metal cables andparticularly of stranded electrical power transmission cables made ofmetallic materials containing aluminum; and, the difficulty associatedwith welding stranded'metal cables is further increased when the cablehas been impregnated with an oil-dielectric. The techniques andapparatus proposed heretofore for welding such power transmission cablesare inadequate in that the resulting junctions provided utilizing thepresent welding apparatus or techniques have low strength, have poorcurrent carrying capacity, and are generally of the type that cannot bereadily accomplished in the field.

SUMMARY This invention provides an improved apparatus for and method ofjoining associated end portions of stranded metal cables such aselectrical power transmission cables to provide a junction in eachinstance having high strength and improved current-carrying capacity.The technique of this invention requires coating of the individualstrands of the end portions to be joined with a suitable cleaning liquidand ejecting a fluid under pressure against such end portions to removesuch liquid and any impurities or foreign particles therefrom. Thecleaned end portionsare then fixed in an improved welding apparatus orfixture and welded together using an access port in such fixture withthe welding action being achieved without damaging or burning away theindividual strands of the cables while assuring that each strand isfused to the weld material. Excess weld material is then removed fromthe junction and in some applications a compression sleeve is fixed inposition thereover to prevent flexing and fatiguing of the weld area andthereby increase the structural integrity of the junction.

Other details, uses, and advantages of this invention will becomeapparent as the following description of the exemplary embodimentsthereof presented in the accompanying drawings proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show presentexemplary embodiments of this invention, in which FIG. 1 is a view withparts in cross section, parts in elevation, and parts broken away of apair of associated end portions of stranded cables which are to bejoined together utilizing the apparatus and method of this invention andparticularly illustrating the manner in which the terminal ends of suchend portions are to be cut to define beveled ends;

FIG. 2 is a view similar to FIG. I particularly illustrating the mannerin which the end portions which are to be joined have electricalinsulation removed therefrom;

FIG. 3 is a view of the end portion of the left cable and particularlyillustrating the manner of applying a cleaning liquid to the individualstrands of the cables;

FIG. 4 is a view similar to FIG. 3 and illustrating the manner ofejecting a fluid under high pressure against the end portion of thecable to remove the cleaning liquid and any foreign particles from theindividual strands in the area to be welded;

FIG. 5 is a perspective view of one exemplary embodiment of the improvedapparatus or fixture of this invention within which the end portion ofthe cleaned stranded cable illustrated in FIG. 4 and the end portion ofthe associated similarly cleaned stranded cable are held in a fixedposition to enable welding thereof;

FIG. 6 is a plan view illustrating the end portions of the strandedcables in position within the fixture of FIG. 5 and showing onetechnique for welding such end portions in position;

FIG. 7 is a view in elevation illustrating the junction defined bywelding the associated end portions together in the fixture of FIG. 5;

FIG. 8 is a view similar to FIG. 7 after removing excess weld materialfrom the welded junction;

FIG. 9 is a view similar to FIG. 8 and illustrating a seamless sleevewhich has been mechanically compressed in position over the weldedjunction;

FIG. I0 is a view similar to FIG. 9 illustrating electrical insulatingmaterial wrapped around the completed junction;

FIG. II is a top plan view of-the fixture of FIG. 5;

FIG. 12 is a front view in elevation with parts broken away of thefixture showing the end portions of the cable to be welded fixed inposition to enable welding thereof; and

FIG. 13 is a view on the line l3--I3 of FIG. 12.

DESCRIPTION OF ILLUSTRATED EMBODIMENTS Reference is now made to FIG. 1of the drawings which illustrates a pair of end portions 20 eachcomprising an associated stranded metal cable, such as stranded aluminumcable, used to transmit electrical power. Each cable 21 of this exampleis in the form of an electrically insulated cable which has a pluralityof layers of oil impregnated paper wrapped therearound to define anelectrically insulating cover 22. This invention provides a simplemethod and an associated welding apparatus or fixture, as will bedescribed hereinafter, which enable associated end portions of strandedaluminum cables to be welded together in a high-strength manner in thefield by workmen having ordinary skill.

With the insulation 22 fixed in position, a bevel 24 is formed in eachend portion 20 and a length of insulation 22 is then stripped from eachend portion in the manner illustrated in FIG. 2 of the drawings. Inthisexample, the end portion 20 of the stranded aluminum cable shown at theright has a section of insulation of greater length removed or strippedtherefrom and for a purpose to be subsequently described.

The bevel 24 in each end portion 20 is preferably fonned by cuttingusing a suitable cutting device. In those applications where the weld ismade in the field, each end portion 20 is preferably held in a holdingdevice 23 and the bevel 24 is cut with an ordinary hacksaw.

Each bevel may be cut at any suitable angle; however, it has been foundthat an angle of 60 with the longitudinal axis of end portion 20provides best results. In addition, by cutting the bevel 24 before theinsulation 22 is removed, a substantially planar cut may be providedwithout deformation of the cable cross section.

After providing the bevel cut 24 in the end portion 20 of each strandedcable 21, the insulation 22 (which is comprised of a plurality ofconcentric layers of oil-impregnated paper) is removed therefrom asindicated in FIG. 2 of the drawings so that each end portion of eachcable 21 is now in the form of a beveled and stripped end portion andfor convenience and ease of presentation, each beveled and stripped endportion will also be referred to as end portion 20. To assure theprovision of a high-strength junction whichis capable of carryingcurrent in an efficient manner, it is necessary that the end portions 20be thoroughly cleaned prior to welding. The cleaning action will bedescribed in connection with the stripped and beveled end portion 20 ofthe cable 21 shown as a left end portion in FIGS. 1 and 2 of thedrawings; however, it will be appreciated that the same cleaning actionis accomplished on the end portion of the associated right cableillustrated in FIG. 2.

Each stranded aluminum cable 21 and hence each end portion 20 iscomprised of a plurality of individual strands 25. The cleaning isachieved as illustrated in FIGS. 3 and 4 by coating the individualstrands 25 with a suitable cleaning fluid and this may be achieved bybrushing the outside layers of the cable strands 25 with a suitableapplicator such as a brush 26 which has been saturated with a cleaningor degreasing agent or liquid such as chlorothane. As the cleaningliquid is applied on the strands 25, a suitable spreading instrumentsuch as an ice pick 30 is used to spread the strands apart and assurethe entire surface of each strand 25 is coated with the cleaning liquid.

Once the individual strands 25 of end portion 20 have been coated, asuitable fluid such as nitrogen or dry air 31 is ejected at highpressure (generally in excess of I p.s.i.g.) through a nozzle 32 againstsuch end portion and during such ejection of high-pressure air, thespreading instrument 30 is again used to spread the individual strands25 apart. The high-pressure air 31 is directed against the terminal endof end portion and inwardly along the length of the cable 21 whereby anyforeign particles such as oil, dirt, metal chips, or the like on aparticular strand are either propelled therefrom or moved inwardly alongthe length of the cable away from the area where the welding action willtake place.

The associated cleaned end portions 20 are then placed in a suitablewelding apparatus or fixture 33 illustrated in FIG. 5 of the drawingsand prior to placing the end portions within fixture 33 a metalcompression sleeve 34 is slid axially inwardly along that end portion 20which has the added length of insulationstripped therefrom so that thesleeve 34 remains outwardly of the fixture 33. The sleeve 34 may be madeof any suitable metallic material; however, inasmuch as the strandedcables 21 are made of aluminum, the sleeve 34 is preferably made of asuitable aluminum alloy.

The fixture 33 is comprised of a lower jaw member 35 and an upper jawmember 36 provided with outwardly concave substantially semicylindricalclamping surfaces 37 and 38 respectively. The surface 37 defines agroove 40 in member 35 while the surface 38 defines a groove 41 in themember 36. The grooves 40 and 41 cooperate to define a substantiallycylindrical channel extending from one end of fixture 33 to the otherand such channel is adapted to receive stripped and cleaned end portions20 of the cables 21 to be joined while the surfaces 37 and 38 cooperateto provide optimum heat conductive contact of such end portions whileholding the end portions firmly in the fixture upon fastening the jawmembers 35 and 36 together.

The upper jaw member 36 has an access opening 42 provided therein whichis sufficiently large to enable a welding device to be insertedtherethrough to weld the end portions 20 together, see FIGS. 5 and 6.The lower member 35 has a well 43 provided therein which communicateswith its grove 40 and the lower member also has a recess 43A definingthe lower portion of the well 43.

Prior to placing the end portions 20 in position in the fixture 33, analuminum disclike slug 44 of oval or circular peripheral outline isplaced in the recess 43A and the slug 44 is used as an arc-startingmember and supplies additional filler metal at the root of the weld. Themembers 35 and 36 are then suitably fixed together with the end portions20 arranged so that their beveled ends face upwardly and are readilyvisible and accessible through the access opening 42.

A suitable welding device, such as a gas-metal-arc welding device (Le, aGMA torch) is used to electric-arc weld the end portions 20 together.The welding sequence is illustrated in FIG. 6 and the welding arc isstarted at 45 using the aluminum slug 44 and moved rapidly to position46. The welding slug 44 eliminates the necessity of establishing the areon the fixture 33 to thereby assure such fixture is not welded to theend portions 20; further, it will be appreciated that the arc should notbe established on the cable strands to prevent unnecessary damage byburning away of cable strands.

The arc is allowed to dwell at position 46 for a sufficient timeinterval to permit weld metal to flow under and fuse the strands 25 ofthe left-end portion 20. As the weld metal begins to build up at cornerposition 46, the arc is moved across the root of the left-end portion 20to position 47 where it is again allowed to dwell until weld metal fusesthe adjoining strands 25. The are is then moved to position 48 and whenweld metal begins to again build up and fuses adjoining strands 25 ofthe right-end portion 20, the arc is moved to position 49 and againallowed to dwell a sufficient time for weld metal to build up and fuseadjoining strands 25.

The movement of the welding arc is repeated in a substantially ovalpattern from positions 46 through 49 and preferably without stoppinguntil weld metal has been built up over the entire height of the cableend. During this welding action, care is taken to assure that the arcdoes not dwell on individual cable strands while assuring that moltenweld material flows between such strands, whereby a high-strength jointor junction is provided and designated by the reference numeral 52 inFIG. 7 of the drawings.

The junction 52 is comprised of a weld nugget 53 of roughly V-shapedconfiguration as viewed from a side thereof. The weld material adheresto the cleaned cable strands, forming a homogeneous weld splice. Inaddition, the weld metal surrounds each strand of each end portionpartially melting some of the outer surface portions of each strand sothat each strand is at least partially embedded within an associatedirregular end portion of the weld nugget 53. Thus, the junction 52 is ofhigh strength and the electrical characteristics of such junction are atleast as good as or better than an equivalent longitudinal section ofunwelded cable 21.

The excess weld material around the junction 52 illustrated in FIG. 7 isremoved by any suitable technique such as filing, sanding, grinding, orthe like, with care being taken to assure that the cable strands are notnicked during this finishing of the junction 52 and the metal cablestrands 25 are not overheated. The finishing or dressing action isachieved until the outside diameter of the junction 52 is substantiallyequal to the outside diameter of the now joined end portions 20 as shownat 56 in FIG. 8.

The sleeve 34 is then moved axially so that the center thereof coincideswith the center of the welded junction 52 and such sleeve is thensuitably radially compressed inwardly utilizing any suitable device suchas a press capable of exerting great forces to provide added strengthfor the welded junction 52. The sleeve 34 extends outwardly of thejunction 52 for substantial distances as indicated at 57 and assuresthat the junction 52 will not be unnecessarily flexed so as to causeweakening thereof.

After careful removal of any burns that may be present on the sleeve orin the vicinity thereof, the junction 52 is wrapped with a suitableelectrical insulating material and this example of the junction has asection 58 of oil-impregnated paper wrapped around junction 52. Thesection 58 provides complete electrical insulation over the entireexposed end portions 20 and overlaps the terminal ends of the layers ofthe insulation remaining on cables 21 to assure provision of acontinuous high-quality electrical insulating sleeve.

Having described an improved method of welding stranded aluminum cable,the detailed description will now proceed with a more detaileddescription of the apparatus or fixture 33, see FIGS. 5, 6, and 11-13,which may be utilized to assure that such method is satisfactorilyaccomplished. The fixture 33 is comprised of lower jaw member 35 andupper jaw member 36 as previously mentioned and such members aresuitably fastened together by a hinge assembly 60. The hinge assembly 60has component portions suitably fixed to the members 35 and 36 and isprovided with a removable hinge pin 61 which enables the members 35 and36 to be separated upon removal of the hinge pin 61 from the assembly60.

The fixture 33 also has a fastening device which is easily fastened andunfastened and is arranged to fasten the members together at a locationopposite the hinge assembly and such fastening device is comprised of aneye bolt 62 having a plain or smooth upper end supported for pivotingmovements by a pivot pin 63 which is supported by a pair of lugs 64extending outwardly from the front face of the upper jaw member 36. Theeye bolt 62 also has a threaded lower or swinging end portion 62A whichhas a nut in the form of a threaded wing nut 65 threaded thereon in aknown manner.

The member 35 has a pair of spaced projections 66 extending outwardlyfrom its front face and defining a slot or groove 67 therebetween whichis adapted to receive the eye bolt 62 therein and once the end portions20 have been suitably installed within the longitudinal channel in thefixture 33 defined by grooves 40 and 41 the wing nut 65 is tightened tothereby clamp its inside surface 70, see FIG. 12, against the lowersurfaces 7i of the projections 66 whereby the jaw members 35 and 36 areheld together in an optimum manner and with the surfaces 37 and 3%clamped on opposite sides of end portions with a small gap or spacebetween jaw members 35 and 36 which assures surfaces 37 and 38 provideoptimum heat-conductive contact against end portions 20.

As will be apparent from FIGS. 6 and 12 of the drawings, the recess 43Ain lower member 35 is particularly adapted to receive the metal disc orslug 44 therewithin to enable establishing an are for electric arcwelding of the end portions 20 of the two illustrated cables 21together. The recess 43A is sufficiently deep that the lower surfaces ofend portions 20 are held substantially in a common plane and hence arenot deflected upwardly, with the slug 44 in position. In one exemplaryfixture of this invention used to weld 56-inch stranded aluminum cable,the recess 43A is of sufficient depth and cross-sectional area toreadily receive an ll/l6-inch diameter slug three thirty-seconds inchthick.

The access opening 42 provided in the upper member 36 is of sufficientsize to enable the tip of a GMA torch to be inserted therein withoutobstruction from the fixture 33 and thereby enables welding by utilizingthe substantially elliptical or oval motion provided by moving in theoval path from points 46 through 49 in the manner previously describedand without obstruction by the upper jaw member 36.

The use of welding fixture 33 assures that heat is concentrated in thearea where the welding action is desired and because of the firmheat-conductive contact of surfaces 37 and 38 against end portions 20,heat is conducted rapidly away from end portions 20 at locationsimmediately adjacent the weld area. To further assure this rapidconduction of heat away from the weld area the access opening 42 andwell 43 are precisely defined. Further, the well 43 is made having awidth which is sufficient to allow weld metal to flow completely aroundend portions 20 to form a pool of weld metal and having a length whichis sufficient to allow weld metal to flow between individual strands yetis short enough to assure the clamping surfaces 37 and 38 engage enoughof end portions 20 to provide optimum conduction of heat away from suchend portions.

In some applications of this invention it may be desired to add coolingfins on the fixture 33 adjacent the opposite ends thereof to assure thatthe heat is dissipated rapidly away from such fixture; and, in otherapplications, it may be desirable to cool the fixture by utilizing asuitable coolant such as water, a refrigerant, or the like.

It will also be appreciated that suitable techniques may be utilized torapidly cool and maintain in a cooled condition the end portion of eachcable 21 adjacent the point where the insulation 22 starts afterdefining stripped end portion 20. This assures that any insulating oil,or the like, comprising the oilimpregnated paper insulating layers willbe presented from running back along the clean individual strands duringthe welding action whereby optimum welding efi'rciency is provided.

The welding fixture 33 may be made of any suitable highlyheat-conductive metallic material. To prevent welding the end portions20 to the fixture, the metallic material used to make the fixture shouldbe different than the metal comprising the cable ends being welded. Forexample, in welding end portions made of copper a steel fixture would bepreferable and in welding aluminum cable ends any heat conductivemetallic material other than aluminum would be preferred.

The above presents a detailed description of the welding of a strandedaluminum electrical power transmission cable; however, it will beappreciated that the method described above and the fixture 33 may beused to weld other stranded cables made of other materials, such ascopper or steel, for example, and irrespective of whether such strandedcables are used as power transmission cables or other types of cables.

As previously indicated, the welding device which is preferred inpracticing the method of this invention is a gasmetal-arc weldingdevice. However, it will also be appreciated that other welding devicesmay be used, such as gas-tungstenare devices, plasma-arc devices,oxyacetylene devices, etc. In addition, it will be appreciated that witharc welding devices, various types of power supplies may be utilized,including pulsed power supplies.

While present exemplary embodiments of this invention, and methods ofpracticing the same, have been illustrated and described, it will berecognized that this invention may be otherwise variously embodied andpracticed within the scope of the following claims.

We claim:

1. A method of joining associated end portions of a pair of strandedcables comprising the steps of, cleaning said end portions, placing saidcleaned end portions on a lower jaw member of a heat-conductive weldingapparatus with the terminal ends of said end portions in axially alignedspaced relation over a well in said lower member, clamping an uppermember of said apparatus against said end portions to achieve optimumheat-conductive contact and with an access opening in said upper membervertically aligned over said well, inserting a welding device throughsaid access opening, welding said end portions together with saidwelding device by forming a pool of welding material in said well, saidwelding material also flowing between individual strands of said endportions to assure welding material fuses adjacent strands to define aweld nugget and a junction having high strength, said clamping stepassuring that during said welding step heat is conducted rapidly awayfrom said junction and reduces the tendency for said end portions toburn back, and cleaning any excess weld material from the weldedjunction after removal from said apparatus.

2. A method as set forth in claim 1 in which said cleaning stepcomprises coating individual strands comprising said end portions with acleaning liquid while separating said strands to assure said liquidcontacts the outside surface of each strand.

3. A method as set forth in claim 2 in which said cleaning liquidcomprises a degreasing liquid and comprising the further step ofejecting a fluid against the terminal end of each end portion whiledirecting said fluid inwardly along the length of the associated cableto force any foreign particles on the individual strands comprising eachend portion away therefrom.

4. A method as set forth in claim 2 particularly adapted for joiningsaid end portions of insulated electrical power transmission cablescomprising the preparation steps of cutting a bevel at the terminal endof each end portion and then removing a length of insulation from eachend portion and comprising the further step of ejecting air underpressure against the terminal end of each end portion while directingsaid air inwardly along the length of the associated cable.

5. A method as set forth in claim 1 for welding said associated endportions of stranded aluminum cables wherein said welding step comprisesforming a pool of molten aluminum welding metal between said individualstrands of said end portions to assure said fusing of adjacent strandsand forming of said weld nugget.

6. A method as set forth in claim 5 in which said inserting stepcomprises inserting said welding device in the fonn of a gas-metal-arcthrough'said access opening.

7. A method as set forth in claim 5 and comprising the preparation stepof placing an aluminum filler slug in said well said inserting stepcomprises inserting said welding device in the form of an electric-arcwelding device through said access opening, and said welding stepcomprises first establishing an electric are on said aluminum fillerslug to enable forming said pool of welding material.

8. A method as set forth in claim 7 in which said welding step comprisesmoving said welding device so that said are is continuously maintainedand moved in an approximately oval path without dwelling on individualstrands of said end portions until the entire junction is defined.

ally sliding said sleeve from a position spaced from said junction to aposition in aligned relation thereover and then compressing saidseamless sleeve in position in a suitable pressing device.

1. A method of joining associated end portions of a pair of strandedcables comprising the steps of, cleaning said end portions, placing saidcleaned end portions on a lower jaw member of a heat-conductive weldingapparatus with the terminal ends of said end portions in axially alignedspaced relation over a well in said lower member, clamping an uppermember of said apparatus against said end portions to achieve optimumheat-conductive contact and with an access opening in said upper membervertically aligned over said well, inserting a welding device throughsaid access opening, welding said end portions together with saidwelding device by forming a pool of welding material in said well, saidwelding material also flowing between individual strands of said endportions to assure welding material fuses adjacent strands to define aweld nugget and a junction having high strength, said clamping stepassuring tHat during said welding step heat is conducted rapidly awayfrom said junction and reduces the tendency for said end portions toburn back, and cleaning any excess weld material from the weldedjunction after removal from said apparatus.
 2. A method as set forth inclaim 1 in which said cleaning step comprises coating individual strandscomprising said end portions with a cleaning liquid while separatingsaid strands to assure said liquid contacts the outside surface of eachstrand.
 3. A method as set forth in claim 2 in which said cleaningliquid comprises a degreasing liquid and comprising the further step ofejecting a fluid against the terminal end of each end portion whiledirecting said fluid inwardly along the length of the associated cableto force any foreign particles on the individual strands comprising eachend portion away therefrom.
 4. A method as set forth in claim 2particularly adapted for joining said end portions of insulatedelectrical power transmission cables comprising the preparation steps ofcutting a bevel at the terminal end of each end portion and thenremoving a length of insulation from each end portion and comprising thefurther step of ejecting air under pressure against the terminal end ofeach end portion while directing said air inwardly along the length ofthe associated cable.
 5. A method as set forth in claim 1 for weldingsaid associated end portions of stranded aluminum cables wherein saidwelding step comprises forming a pool of molten aluminum welding metalbetween said individual strands of said end portions to assure saidfusing of adjacent strands and forming of said weld nugget.
 6. A methodas set forth in claim 5 in which said inserting step comprises insertingsaid welding device in the form of a gas-metal-arc through said accessopening.
 7. A method as set forth in claim 5 and comprising thepreparation step of placing an aluminum filler slug in said well saidinserting step comprises inserting said welding device in the form of anelectric-arc welding device through said access opening, and saidwelding step comprises first establishing an electric arc on saidaluminum filler slug to enable forming said pool of welding material. 8.A method as set forth in claim 7 in which said welding step comprisesmoving said welding device so that said arc is continuously maintainedand moved in an approximately oval path without dwelling on individualstrands of said end portions until the entire junction is defined.
 9. Amethod as set forth in claim 1 and comprising the further step of fixinga sleeve around the weld defining said junction to prevent flexingmovements of said junction and thereby improve the structural integritythereof.
 10. A method as set forth in claim 9 in which said sleevecomprises a seamless sleeve and said fixing step comprises axiallysliding said sleeve from a position spaced from said junction to aposition in aligned relation thereover and then compressing saidseamless sleeve in position in a suitable pressing device.